Rapid aqueous photo-polymerization route to polymer and polymer-composite hydrogel 3D inverted colloidal crystal scaffolds

Successful regeneration of biological tissues in vitro requires the utilization of three-dimensional (3D) scaffolds that provide a near natural microenvironment for progenitor cells to grow, interact, replicate, and differentiate to form target tissues. In this work, a rapid aqueous photo-polymerization route was developed toward the fabrication of a variety of polymer hydrogel 3D inverted colloidal crystal (ICC) scaffolds having different physical and chemical properties. To demonstrate the versatility of this technique, a variety of polymer hydrogel ICC scaffolds were prepared, including (1) polyacrylamide (pAAM) scaffolds, (2) poly(2-hydroxyethyl methacrylate) (pHEMA) scaffolds, (3) poly(2-hydroxyethyl acrylate) (pHEA) scaffolds, and composite scaffolds including (4) pAAM-pHEMA scaffolds, (5) pHEMA-pMAETAC [poly(2-methacryloyloxy) trimethyl ammonium] scaffolds, and (6) pHEA-pMEATAC scaffolds. Templates for scaffolds incorporated both uniform sized (104 μm diameter) and nonuniform sized (100 ± 20 μm diameter) closely packed noncrosslinked poly(methyl methacrylate) beads. Human bone marrow stromal HS-5 cells were cultured on the six different types of scaffolds to demonstrate biocompatibility. Experimental results show that cells can remain viable in these scaffolds for at least 5 weeks. Of the six scaffolds, maximal cell adhesion and proliferation are obtained on the positively charged composite hydrogel pHEMA-pMEATAC and pHEA-pMAETAC scaffolds.